GEOLOGIC TIMELINE Cenozoic
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Chapter 30. Latest Oligocene Through Early Miocene Isotopic Stratigraphy
Shackleton, N.J., Curry, W.B., Richter, C., and Bralower, T.J. (Eds.), 1997 Proceedings of the Ocean Drilling Program, Scientific Results, Vol. 154 30. LATEST OLIGOCENE THROUGH EARLY MIOCENE ISOTOPIC STRATIGRAPHY AND DEEP-WATER PALEOCEANOGRAPHY OF THE WESTERN EQUATORIAL ATLANTIC: SITES 926 AND 9291 B.P. Flower,2 J.C. Zachos,2 and E. Martin3 ABSTRACT Stable isotopic (d18O and d13C) and strontium isotopic (87Sr/86Sr) data generated from Ocean Drilling Program (ODP) Sites 926 and 929 on Ceara Rise provide a detailed chemostratigraphy for the latest Oligocene through early Miocene of the western Equatorial Atlantic. Oxygen isotopic data based on the benthic foraminifer Cibicidoides mundulus exhibit four distinct d18O excursions of more than 0.5ä, including event Mi1 near the Oligocene/Miocene boundary from 23.9 to 22.9 Ma and increases at about 21.5, 18 and 16.5 Ma, probably reßecting episodes of early Miocene Antarctic glaciation events (Mi1a, Mi1b, and Mi2). Carbon isotopic data exhibit well-known d13C increases near the Oligocene/Miocene boundary (~23.8 to 22.6 Ma) and near the early/middle Miocene boundary (~17.5 to 16 Ma). Strontium isotopic data reveal an unconformity in the Hole 926A sequence at about 304 meters below sea ßoor (mbsf); no such unconformity is observed at Site 929. The age of the unconfor- mity is estimated as 17.9 to 16.3 Ma based on a magnetostratigraphic calibration of the 87Sr/86Sr seawater curve, and as 17.4 to 15.8 Ma based on a biostratigraphic calibration. Shipboard biostratigraphic data are more consistent with the biostratigraphic calibration. -
Timeline of Natural History
Timeline of natural history This timeline of natural history summarizes significant geological and Life timeline Ice Ages biological events from the formation of the 0 — Primates Quater nary Flowers ←Earliest apes Earth to the arrival of modern humans. P Birds h Mammals – Plants Dinosaurs Times are listed in millions of years, or Karo o a n ← Andean Tetrapoda megaanni (Ma). -50 0 — e Arthropods Molluscs r ←Cambrian explosion o ← Cryoge nian Ediacara biota – z ←Earliest animals o ←Earliest plants i Multicellular -1000 — c Contents life ←Sexual reproduction Dating of the Geologic record – P r The earliest Solar System -1500 — o t Precambrian Supereon – e r Eukaryotes Hadean Eon o -2000 — z o Archean Eon i Huron ian – c Eoarchean Era ←Oxygen crisis Paleoarchean Era -2500 — ←Atmospheric oxygen Mesoarchean Era – Photosynthesis Neoarchean Era Pong ola Proterozoic Eon -3000 — A r Paleoproterozoic Era c – h Siderian Period e a Rhyacian Period -3500 — n ←Earliest oxygen Orosirian Period Single-celled – life Statherian Period -4000 — ←Earliest life Mesoproterozoic Era H Calymmian Period a water – d e Ectasian Period a ←Earliest water Stenian Period -4500 — n ←Earth (−4540) (million years ago) Clickable Neoproterozoic Era ( Tonian Period Cryogenian Period Ediacaran Period Phanerozoic Eon Paleozoic Era Cambrian Period Ordovician Period Silurian Period Devonian Period Carboniferous Period Permian Period Mesozoic Era Triassic Period Jurassic Period Cretaceous Period Cenozoic Era Paleogene Period Neogene Period Quaternary Period Etymology of period names References See also External links Dating of the Geologic record The Geologic record is the strata (layers) of rock in the planet's crust and the science of geology is much concerned with the age and origin of all rocks to determine the history and formation of Earth and to understand the forces that have acted upon it. -
21. BRYOZOA from SITE 282 WEST of TASMANIA Robin E
21. BRYOZOA FROM SITE 282 WEST OF TASMANIA Robin E. Wass and J. J. Yoo, Department of Geology and Geophysics, University of Sydney, Australia ABSTRACT More than 15,000 bryozoan fragments have been identified from 17 samples in the late Miocene and late Pleistocene sediments at Site 282, Leg 29, Deep Sea Drilling Project, off the west coast of Tas- mania (lat 42°14.76'S, long 143°29.18'E). Bryozoa are referable to the Orders Cyclostomata and Cheilostomata and represent 79 species belonging to 48 genera. Both late Miocene and late Pleisto- cene assemblages are closely related to assemblages found in the Tertiary of southern Australia, and the Recent of the southern Aus- tralian continental shelf. INTRODUCTION The bryozoan fauna is small relative to that found in the late Pleistocene sediments and relative to records of Recent and Tertiary bryozoan faunas from southern late Miocene Bryozoa from southeastern Australia. The Australia have been documented for more than a late Miocene Bryozoa in the Tertiary of southeastern century. The dominant works have been by MacGilli- Australia are also greatly diminished when compared vray (1879, 1895), Maplestone (1898), Stach (1933), and with the middle Miocene faunas. Few studies have been Brown (1958). Brown's monograph (1952) on the New made of Pliocene bryozoa in southeastern Australia, but Zealand Tertiary Bryozoa, recorded genera and species apparently bryozoans are fewer in number than in the from the Recent and Tertiary of southern Australia. late Miocene. While a great deal of work has been done, there are still The fauna observed at Site 282 is composed almost a large number of studies which have to be completed entirely of four zoarial types—catenicelliform, cellari- before the bryozoan faunas are properly understood. -
Asteroid Impact, Not Volcanism, Caused the End-Cretaceous Dinosaur Extinction
Asteroid impact, not volcanism, caused the end-Cretaceous dinosaur extinction Alfio Alessandro Chiarenzaa,b,1,2, Alexander Farnsworthc,1, Philip D. Mannionb, Daniel J. Luntc, Paul J. Valdesc, Joanna V. Morgana, and Peter A. Allisona aDepartment of Earth Science and Engineering, Imperial College London, South Kensington, SW7 2AZ London, United Kingdom; bDepartment of Earth Sciences, University College London, WC1E 6BT London, United Kingdom; and cSchool of Geographical Sciences, University of Bristol, BS8 1TH Bristol, United Kingdom Edited by Nils Chr. Stenseth, University of Oslo, Oslo, Norway, and approved May 21, 2020 (received for review April 1, 2020) The Cretaceous/Paleogene mass extinction, 66 Ma, included the (17). However, the timing and size of each eruptive event are demise of non-avian dinosaurs. Intense debate has focused on the highly contentious in relation to the mass extinction event (8–10). relative roles of Deccan volcanism and the Chicxulub asteroid im- An asteroid, ∼10 km in diameter, impacted at Chicxulub, in pact as kill mechanisms for this event. Here, we combine fossil- the present-day Gulf of Mexico, 66 Ma (4, 18, 19), leaving a crater occurrence data with paleoclimate and habitat suitability models ∼180 to 200 km in diameter (Fig. 1A). This impactor struck car- to evaluate dinosaur habitability in the wake of various asteroid bonate and sulfate-rich sediments, leading to the ejection and impact and Deccan volcanism scenarios. Asteroid impact models global dispersal of large quantities of dust, ash, sulfur, and other generate a prolonged cold winter that suppresses potential global aerosols into the atmosphere (4, 18–20). These atmospheric dinosaur habitats. -
Reduced El Niño–Southern Oscillation During the Last Glacial
RESEARCH | REPORTS PALEOCEANOGRAPHY vergent results and our newly generated data by considering geographic location, choice of fora- minifera species, and changes in thermocline – depth (see supplementary materials). Reduced El Niño Southern Oscillation ENSO variability is asymmetric (the El Niño warm phase is more extreme than the La Niña during the Last Glacial Maximum cold phase) (14), so temperature variations in the equatorial Pacific are not normally distrib- Heather L. Ford,1,2* A. Christina Ravelo,1 Pratigya J. Polissar2 uted (7, 15), and statistical tests that assume normality (e.g., standard deviation) can lead to El Niño–Southern Oscillation (ENSO) is a major source of global interannual variability, but erroneous conclusions with respect to changes its response to climate change is uncertain. Paleoclimate records from the Last Glacial in variance. Therefore, we use quantile-quantile Maximum (LGM) provide insight into ENSO behavior when global boundary conditions (Q-Q) plots—a simple, yet powerful way to vi- — (ice sheet extent, atmospheric partial pressure of CO2) were different from those today. sualize distribution data to compare the tem- In this work, we reconstruct LGM temperature variability at equatorial Pacific sites perature range and distribution recorded by two using measurements of individual planktonic foraminifera shells. A deep equatorial populations of individual foraminifera shells to thermocline altered the dynamics in the eastern equatorial cold tongue, resulting in interpret possible climate forcing mechanisms. reduced ENSO variability during the LGM compared to the Late Holocene. These results Sensitivity studies using modern hydrographic suggest that ENSO was not tied directly to the east-west temperature gradient, as data show how changes in ENSO and seasonality previously suggested. -
Exhibit Specimen List FLORIDA SUBMERGED the Cretaceous, Paleocene, and Eocene (145 to 34 Million Years Ago) PARADISE ISLAND
Exhibit Specimen List FLORIDA SUBMERGED The Cretaceous, Paleocene, and Eocene (145 to 34 million years ago) FLORIDA FORMATIONS Avon Park Formation, Dolostone from Eocene time; Citrus County, Florida; with echinoid sand dollar fossil (Periarchus lyelli); specimen from Florida Geological Survey Avon Park Formation, Limestone from Eocene time; Citrus County, Florida; with organic layers containing seagrass remains from formation in shallow marine environment; specimen from Florida Geological Survey Ocala Limestone (Upper), Limestone from Eocene time; Jackson County, Florida; with foraminifera; specimen from Florida Geological Survey Ocala Limestone (Lower), Limestone from Eocene time; Citrus County, Florida; specimens from Tanner Collection OTHER Anhydrite, Evaporite from early Cenozoic time; Unknown location, Florida; from subsurface core, showing evaporite sequence, older than Avon Park Formation; specimen from Florida Geological Survey FOSSILS Tethyan Gastropod Fossil, (Velates floridanus); In Ocala Limestone from Eocene time; Barge Canal spoil island, Levy County, Florida; specimen from Tanner Collection Echinoid Sea Biscuit Fossils, (Eupatagus antillarum); In Ocala Limestone from Eocene time; Barge Canal spoil island, Levy County, Florida; specimens from Tanner Collection Echinoid Sea Biscuit Fossils, (Eupatagus antillarum); In Ocala Limestone from Eocene time; Mouth of Withlacoochee River, Levy County, Florida; specimens from John Sacha Collection PARADISE ISLAND The Oligocene (34 to 23 million years ago) FLORIDA FORMATIONS Suwannee -
Matheus Souza Lima Ribeiro
Palaeogeography, Palaeoclimatology, Palaeoecology 392 (2013) 546–556 Contents lists available at ScienceDirect Palaeogeography, Palaeoclimatology, Palaeoecology journal homepage: www.elsevier.com/locate/palaeo Climate and humans set the place and time of Proboscidean extinction in late Quaternary of South America Matheus Souza Lima-Ribeiro a,b,⁎, David Nogués-Bravo c,LeviCarinaTerribilea, Persaram Batra d, José Alexandre Felizola Diniz-Filho e a Departamento de Ciências Biológicas, Universidade Federal de Goiás, Campus Jataí, Cx. Postal 03, 75804-020 Jataí, GO, Brazil b Programa de Pós-graduação em Ecologia e Evolução, Universidade Federal de Goiás, Cx. Postal 131, 74001-970 Goiânia, GO, Brazil c Centre for Macroecology, Evolution and Climate, University of Copenhagen, Universitetsparken 15, 2100, Denmark d Department of Geology, Greenfield Community College, Greenfield, MA 01301, USA e Departamento de Ecologia, ICB, Universidade Federal de Goiás, Cx. Postal 131, 74001-970 Goiânia, GO, Brazil article info abstract Article history: The late Quaternary extinctions have been widely debated for a long time, but the varying magnitude of Received 18 April 2013 human vs. climate change impacts across time and space is still an unresolved question. Here we assess Received in revised form 7 October 2013 the geographic range shifts in response to climate change based on Ecological Niche Models (ENMs) and Accepted 21 October 2013 modeled the timing for extinction under human hunting scenario, and both variables were used to explain Available online 30 October 2013 the extinction dynamics of Proboscideans during a full interglacial/glacial cycle (from 126 ka to 6 ka) in South America. We found a large contraction in the geographic range size of two Proboscidean species stud- Keywords: Late Quaternary extinctions ied (Cuvieronius hyodon and Notiomastodon platensis) across time. -